E. Wilson and J. Shipman — The Keuper Basement Beds. 533 



these formations there have been observed to intervene certain de- 

 posits that agree both in mineral composition and in physical cha- 

 racters with the white sandstones and conglomerates, known as the 

 " Basement Beds," l that form so important a feature in the Keuper 

 of the West Midlands. 



The Hunger Hills. — These " Basement Beds " were exposed to 

 view during the progress of some excavations on the Hunger Hill 

 Boad, Nottingham, and a good section showing their junction with 

 the Bunter Pebble Beds was supplied by a cutting for a culvert in 

 Beverley Street. These rocks here consist of soft coarse and 

 " sharp " grained white micaceous sandstone. Owing to inequalities 

 in the surface of the Bunter, they vary rapidly in thickness from a 

 few inches only to as much as six feet. Throughout the sand- 

 stone are scattered quartzite pebbles like those of the " Pebble 

 Beds," but it was in the cavities in the old surface of the Bunter 

 that the pebbles were mostly met with. Two deep furrows in 

 the Bunter surface trended from west to east, shallowing out on 

 the west. About two hundred feet further east, the white sand- 

 stones were again found resting on a ridged and undulating surface 

 of the "Pebble Beds." The "Basement Beds" were not at this 

 spot proved over a greater space than about 25CK x 300', being 

 cut off and overlapped by the Keuper dolomitic conglomerate on 

 all sides, except the north-east, where they were lost to view 

 beneath the Lower Keuper Sandstone of the Hunger Hills. They 

 appear to occupy a shallow cavity eroded out of a plane of Bunter 

 sloping to the east at about one in fifty. The upper surface of the 

 white sandstone itself showed distinct signs of erosion, being worn 

 into irregular hummocks and cavities, filled in with the rusty-coloured 

 sand and pebbles of the Keuper conglomerate. 



Cohoick. — The "Basement Beds" were also exposed in the tunnel 

 for the Leen Valley Outfall Sewer, at Bough Hill Wood, near 

 Nottingham. 2 These Beds consist of at least twenty feet of massive 

 light-grey micaceous and felspathic sandstone, grit and conglomerate, 

 with lenticular seams of red marl. False-bedding is prevalent in the 

 sandstones, the planes sloping east at from 5° to 25°. The pebbles 

 are nearly all quartzites or quartz, and agree with those of the 

 Bunter Pebble Beds, except that many of them have chipped 

 corners or angular faces as if fractured during transport or the pro- 

 cess of deposition. In the tunnel heading near the top of the series 

 is a bed of marl, that for a space of about a hundred feet maintains a 

 thickness of from two to four feet, and then becomes split up into 

 wedges that dovetail in a peculiar manner with the beds of sandstone 

 and conglomerate that it locally displaces. These beds show signs 



1 Hull, " Triassic and Permian Bocks of the Midlands," pp. 66, et seq. 



3 We are indebted to C. F. Gripper, Esq., contractor for the works, and to M. 0. 

 Tarbotton, Esq., F.G.S., Engineer to the Nottingham Corporation, for the lower 

 portion of the third section, which was arrived at by means of a shaft sunk for the 

 purpose at Rough Hill Wood ; but owing to the water-level of the Trent valley 

 being reached, the sinking had to be abandoned without proving the Bunter. 



In consequence of the great length of two of the sections referred to, their pub- 

 lication with the present paper has been abandoned by its authors. 



